The lower-left and upper-right blocks are there for suppression; one of them could probably be replaced by something more complex to make it into a p87 gun. The previous smallest gun and oscillator of this period seem to be variants of this, from the Variable-Speed Firing Squad thread:

Not at all. In fact, I would go so far as to say it is one of the most clever and interesting oscillators to be discovered. The Pi -> R -> Pi reaction is unique, I think, in that it does not rely on any symmetry. The Pi and the R just happen to appear in exactly the right places. The solution to the conflicting block and eater is also very beautiful. It's lucky that there was even a working combination of two engines.

A 2-p87 non-exhaustive by-hand search found (left to right) a relatively large spark, 3 HF factories, a too-close R output and a glider + junk with a little (read: almost certainly not enough) room for catalysis.

Sokwe wrote:Not at all. In fact, I would go so far as to say it is one of the most clever and interesting oscillators to be discovered. The Pi -> R -> Pi reaction is unique, I think, in that it does not rely on any symmetry. The Pi and the R just happen to appear in exactly the right places. The solution to the conflicting block and eater is also very beautiful. It's lucky that there was even a working combination of two engines.

Well, when you put it that way, thanks!

BlinkerSpawn wrote:A 2-p87 non-exhaustive by-hand search found (left to right) a relatively large spark, 3 HF factories, a too-close R output and a glider + junk with a little (read: almost certainly not enough) room for catalysis.

Nice. Let's skip forward: Apparently the eaters near the loaves just suppress B-heptomino precursors that otherwise just unsalvageably ruin everything--it wasn't clear from the CatForce result. These can be fiddled into Pi precursors instead, and then taking some inspiration from the p45 gun...it's easier to just post this:

Logged in just to say congrats! Wow! The two conduits were pretty miraculous (encountered by dedicated search and the ability to recognize it, by the way) but I can see a non-trivial job done there. I guess you've rubbed one half of that with a p3?

It has a couple of sparks, but at first glance they don't seem to be good for anything that can't already be done by known p8 oscillators. E.g. here it deletes half of a p20 glider stream, in the same way that a blocker can:

In its current form, the program only works for totalistic rules and for David Bell's "Just Friends" rule, which is like B2/S12 except that birth only occurs if the 2 parents are not orthogonally adjacent. To handle other non-totalistic rules (with a 3x3 neighborhood), I think that you just need to modify the "nxgen" function appropriately. (But I wrote the program almost 20 years ago, so I don't remember all the details of how it works; it's possible that there are other things that would need to be changed.)

What do you mean by "exploding rules"? The program should work fine for rules like B2/S2345, which tend to expand in all directions, but leave behind mostly stable stuff. Any oscillators that it finds would work within that stuff, but there's no guarantee that a finite stator would exist.